Timer for Fan

[Neal]

I have a simple pull switch fan in my shower room. It also has a window, so no desperate need for ventilation, but I would like to run the fan for a while after a shower to avoid excess humidity/condensation.

Can I buy some sort of timer switch?

It is currently wired Live and Neutral from a fused box outside the room (There is space here for a switch/relay/whatever)

The pull switch at the fan simply connects the live to the motor.

I could easily replace the 2 core with 3 core, if needed (probably), but I think the pull switch is only a single pole (problem?).

I would like for a pull on the switch to start the fan, and leave it running for 1/2 hour or so.

I can see that I would probably need 2 pulls ('off' then 'on') to start it the next time - this is not a problem

It seems to me I need a switch (relay?) which powers up when power is applied, and powers down after a set time, even if power is STILL applied

So, suggestions? Links to equipment? Alternative approaches?

Neal

Sorry for the poor terminology - I could easily draw the circuit, and a little diagram to describe it, but my ASCII art isn't up to scratch to present it here.

And I am also aware of the regs w.r.t wiring in bathrooms etc.

[Malcolm Race]

Look at TLC remote timer EK 320A. I am using one to switch off heating in a rented hall (which is on a time clock in a locked cupboard) for 30 mins using a relay to invert the action. IIRC the time is adjustable in two or three ranges.

Malcolm

[charlieB]

Another option is to replace the fan with one with an inbuilt timer. e.g.

requires a 3-core + earth feed to it - one core of which is the "trigger" that is connected to the light circuit, the other two being L+N so it has its own power. They also sell 3 pole fan isolator switches.

Charlie

[Owain]

An ordinary fan timer module will work if you replace the pull switch with a momentary-action one. You can also get momentary-action ceiling pull switches.

Owain